Tubes intended in particular for the oil industry or for transporting fluids, are generally tested at high pressures prior to being delivered to end users, thereby setting up stresses in the tubes close to their elastic limits.
In order to perform this hydraulic test, a tube is placed on a bench having a closure head at each end of the tube for closing the end of the tube and for sealing it.
One of the closure heads is fed with water in order to put the tube under test. The structure of the bench is suitable for withstanding the large thrusts induced by the test hydraulic pressure acting on the closed surface at each end.
Thus, the present invention relates to a closure head for a hydraulic tube-testing bench, the head comprising a head body including a first bore into which one end of a tube may be freely inserted, a second bore of larger diameter than the first bore with a resilient sealing ring being inserted at the end of the second bore, means for conveying a fluid under pressure into a chamber constituted between the outer periphery of the sealing ring and said second bore enabling the sealing ring to be contracted against said tube, said sealing ring being prevented from moving axially on its side furthest from the end of the tube by an annular series of thrust sectors which are independent from said sealing ring, said sectors including sliding control means enabling them to be clamped against the tube and also enabling them to be retracted away therefrom, said sectors including axial retention means on their sides furthest from said sealing ring.
A closure head constituted in this way is disclosed in U.S. Pat. No. 4,537,407.
However, the sealing ring 10 is accessible with difficulty and a plurality of parts must be disassembled whenever it is to be replaced and this must be done for all of the sectors separately.
The aim of the present invention is to provide a closure head enabling the sealing ring to be replaced very quickly and easily. It also aims at providing improved retention of the sealing ring by leaving no interstitial passages, and finally to make use of only one control for tightening and untightening the thrust sectors.